Add fused desktop binaries (win/mac/linux) to the pipeline

Fuse the .love into the official LÖVE 11.5 release artifacts: win-x64
(love.exe concat + dlls), mac-universal (love.app bundle, Info.plist
patched) and linux-x64 (AppImage rebuilt via readelf offset +
unsquashfs/mksquashfs — the AppImage runtime is glibc-linked and
cannot run on the alpine builder). The builder image pre-fetches the
dist files to /opt/love-dist and gains squashfs-tools + binutils.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

example-woodpecker.yaml

@@ -10,6 +10,11 @@ steps:
     commands:
       - make ci-export
 
+  - name: binaries
+    image: git.teletypegames.org/internal/love-builder:latest
+    commands:
+      - make ci-binaries
+
   - name: upload
     image: alpine
     environment: